C H R 



[89] 



CHE 



markings to the internal structure 

 of the choanite, and these are 

 worked into a variety of ornaments, 

 as brooches, buckles, earrings, &c. 



CHOKE-DAMP. A name given by 

 miners to carbonic acid. 



CHO'NDRODITE. Hemiprismatic chry- 

 solite. Another name for brucite ; 

 a mineral composed of magnesia 

 54, silica 32, fluoric acid 4, oxide 

 of iron 2, potass 1, and water 1. 



CHONDROPTER'YGII. One of the two 

 great divisions in the classification 

 of fishes, comprising all the cartila- 

 ginous genera. The cartilaginous 

 fishes Chondropterygii of Cuvier. 

 Hugh Miller. 



CHONDROPTER'YGIAN. Belonging to 

 the division of fishes named Chon- 

 dropterygii. 



The cartilaginous or chondroptery- 

 gian fishes. The long-fronted 

 chondropterygian series of Cuvier. 

 Hugh Miller. 



CHROMATE. A mineral containing 

 chromic acid with a base, as chro- 

 mate of lead. 



CHRI'STTANITE. An earthy mineral 

 so named by Monticelli, after 

 Prince Christian of Denmark. See 

 A.northite. 



CHROME. | (from x/V*^ a > colour, 



CnRo'MruM. j Gr.) This mineral 

 is said to have obtained its name 

 from the property it possesses of 

 imparting colour to other bodies in 

 a very remarkable degree. Chro- 

 mium was first discovered by 

 Vauquelin in 1797, after a variety 

 of discordant analyses made by 

 Macquart, Bindheim, and others. 

 Specific gravity about 5-0. Its 

 principal ore is found in Siberia, 

 and is a salt of lead, formed by an 

 acid oxide of chromium. To the 

 presence of chrome the emerald 

 and the ruby owe their hues. It 

 is used in tinting glass of an 

 emerald green. 



CHRYSOBE'RYL. (from x/>v<ros, gold, 

 and prjpvKkiov, gemma.) The 

 cymophane of Haiiy. Chrysopal of 



Delametherie. Werner first made 

 the chrysoberyl a distinct species, 

 and gave it the name which it now 

 bears. Colour, a light yellowish or 

 asparagus green. This gem is 

 found in the Brazils, in Ceylon, in 

 America, and in Siberia. It occurs 

 in the alluvial deposits of rivers, 

 and consequently in rolled and 

 frequently much worn masses; 

 also chrystallized. It consists of 

 alumina 76 -75, glucina 17- 79, and 

 protoxide of iron 4*50, according 

 to Thomson; Klaproth's analysis 

 gives alumina 71*5, lime 6*0, 

 silica 18'0, oxide of iron 1*5. 

 Its specific gravity 3 '6 to 3 -8, 

 hardness = 8 '5. " The primary 

 form of its crystal is a right rec- 

 tangular prism. By friction it 

 becomes electric. Alone it is 

 infusible before the blow-pipe, but 

 with borax it melts slowly, forming 

 a transparent glass. It displays a 

 beautifully changeable play of 

 light. When free from flaws it is 

 a handsome gem, but not of the 

 first order in value. 

 CHRY'SOLITE. (from x/avo-o? gold, 

 and A/005, a stone, chrysolite, Fr.) 

 The Peridot of Haiiy, and Kriso- 

 lith and Olivin of Werner. The 

 term chrysolite was applied, with- 

 out any regard to distinction, 

 or any discrimination, to a great 

 variety of precious stones, till 

 Werner defined it accurately, and 

 confined it to that stone which the 

 French mineralogists distinguish by 

 the appellation of Peridot (sorte de 

 pierre precieuse, peu recherchee, 

 qui tire un peu sur le vert.) Chry- 

 solite contains a very large pro- 

 portion of magnesia, according to 

 some authorities more than half its 

 weight, but agreeably to the ana- 

 lysis of others from forty to fifty 

 per cent. Chrysolite is of a green 

 colour, inclining to yellow; its 

 texture is foliated; fracture con- 

 choidal. It causes double refrac- 

 tion. It is infusible at 150, but 



